How to pinch Geraniums?
I slide my fingers down the stem behind the flower and pinch as low as possible. It will work just snapping the flower off but you don’t want the flowerless stem showing. Also when you buy the new geranium before planting you should remove all open or partially opened flowers. This will let the plant put all it’s strength into the root system first. That in turn will give you a better display of flowers later in the season.